P2E8F: Battery Charger B Charge Sequence Signal 2 Circuit Low

What it means

The charge sequence signal 2 circuit of battery charger B reports voltage below the expected window. Charging handshake compromised.

At a glance

• Usually lights the check-engine light
• The engine or gearbox may go into limp mode

How it works

Battery charger B uses charge-sequence signal 2 to participate in the charging handshake. The control module sets this code when signal 2 is below its expected range, so charger B may not communicate correctly even if signal 1 is normal.

Common causes

Most likely first.

1. Signal wire shorted to ground
2. Open in signal wire
3. Connector pins corroded - high contact resistance

Symptoms

• Charge status indicator shows fault
• Charging may not start or interrupts
• Slower-than-expected charge rate

How to diagnose it

1. Review charger-related codes and freeze-frame data, and record whether charging fails to start, stops, or runs slowly.
2. Inspect the signal 2 connector and harness for corrosion, loose pins, broken insulation, or an open connection.
3. With the system safely isolated according to the vehicle procedure, check whether signal 2 is shorted to ground.
4. Measure signal 2 at the appropriate connector and compare it with the manufacturer's specification to verify the low reading.
5. If no ground short is found, test signal 2 continuity and the charger B input using the manufacturer's procedure.

Common fixes

• Clean corroded connector contacts and secure the signal 2 connection.
• Repair a signal 2 wire shorted to ground.
• Repair a broken or open signal 2 wire.
• Repair or replace charger B only if its signal 2 input fails testing with intact wiring.

Can I keep driving?

Charging may fail to start, stop unexpectedly, or remain slower than expected. Keep enough charge for your plans and avoid relying on charger B until the low signal is diagnosed and repaired.